Can you wash your hair with soap or shower gel?
Can you wash your hair with shower gel or soap? As a stopgap, yes, once in a while. For regular use, it is best avoided: these products are formulated for the skin on your body, and their pH and cleansing agents can upset the scalp, encourage dandruff and leave hair dull and brittle.
Here is what happens when you wash your hair with shower gel or soap, and how to limit the damage if you have nothing else to hand.
Shampoo, soap, shower gel: what is the difference?
Shampoos, soaps and shower gels have one thing in common: they all contain surfactants, cleansing agents that remove impurities, excess sebum and bacteria. That is where the similarities end.
A shampoo is formulated for the scalp and the hair fibre. Its pH, the gentleness of its cleansing agents and its care ingredients are chosen to cleanse without stripping and to leave hair supple and easy to style. A soap or shower gel is designed for the skin on your body, which has neither the same needs nor the same sensitivity.
Why does pH matter so much for hair?
Hair and skin have a different sensitivity to the pH of the products applied to them. The scalp is naturally slightly acidic, and the hair cuticle, made of tiny scales, stays smooth and closed in an acidic environment.
Soap has an alkaline pH, at around 10. The pH of shower gels varies by formula, but they are still designed for the skin on your body, not for the hair fibre. Shampoos have a much lower pH: Homnès solid shampoos, for example, have a pH between 5 and 6.5.
An alkaline product tends to lift the hair's cuticle scales. The fibre becomes more porous: it snags, tangles and loses its shine.
What happens if you wash your hair with shower gel?
Used regularly, shower gel or body soap can:
- damage the hydrolipidic film that protects the hair, leaving it dry and dull;
- strip the scalp, which can feel tight, itch and develop dandruff;
- make hair get greasy faster: the scalp protects itself from this aggression by producing large amounts of sebum, which makes hair oily;
- make hair brittle and hard to detangle, for lack of care ingredients.
With soap, hard water adds another drawback: limescale reacts with soap and can leave a light film on the hair that weighs it down and dulls it.
Can you wash your hair with soap?
The reasoning is the same for toilet soap, liquid or solid: its alkaline pH suits the skin on your body but disrupts the scalp and the cuticle. So keep your silk soaps for your body and save shampoo for your hair.
A solid shampoo looks like a soap, but its formula is different: it is designed for hair, with a pH suited to the scalp.
Is shower gel for hair? What it does not give your hair
Soaps and shower gels do not contain the ingredients needed to have cosmetic effects on hair. Homnès solid shampoos, for example, contain naturally derived D-panthenol (or provitamin B5), which acts like a cement to hold the cuticle scales together better. The hair is repaired: less porous, it is stronger, more supple, shinier and easier to style.
Keeping hair healthy is a delicate balance that soap cannot provide. Each hair type has its own formula:
- the solid shampoo for normal hair, for gentle everyday washing;
- the nourishing solid shampoo, which deeply strengthens dry, brittle hair thanks to a patiently developed recipe;
- the purifying solid shampoo, which absorbs excess sebum thanks to its many minerals and cleanses the scalp without irritating it.
Not sure which one to choose? Our online hair diagnosis points you to the right care for your hair.
Using shower gel as shampoo in a pinch: how to limit the damage
It is best to avoid using soap or shower gel to wash your hair, except when you have absolutely no choice: you forgot your shampoo when travelling, at the gym or camping. In that case:
- use a small amount and concentrate it on the scalp, without rubbing the lengths;
- rinse for a long time with lukewarm water;
- then apply a conditioner to the lengths to minimise the damage;
- go back to your usual shampoo at the next wash.
So you are never caught out again, a solid shampoo slips easily into a travel kit or gym bag.
Frequently asked questions
Can I use shower gel as shampoo?
Occasionally, yes. Day to day, it is best avoided: it is formulated neither for the scalp nor for the hair fibre, and contains no care ingredients for hair.
Does washing your hair with soap cause dandruff?
Repeated use can upset the scalp and encourage dandruff. If dandruff persists after going back to a suitable shampoo, ask a dermatologist for advice.
Can you wash oily hair with soap?
It is best avoided. By stripping the scalp, soap prompts it to produce more sebum, and hair gets greasy faster.
Also worth reading: